This application relates to footwear and, in particular, to sole and heel structures for shoes, boots or the like. The application relates in particular to footwear structures incorporating fluid-filled cavities for providing cushioning, forward thrust and the like.
Various types of footwear structures having fluid-containing cavities or systems have heretofore been provided. Some of the structures have included a molded outsole with cavity-defining bulges therein which are closed by an overlying midsole, communication between the bulges being provided through narrow, restricted channels or passageways to accommodate movement of fluid back and forth between the cavities. Other structures have incorporated closed, flexible bladders with expandable fluid-filled pockets, which may also be interconnected by narrow restricted passageways. In some prior structures, the pockets of such bladders have been accommodated in cavities in an outsole and/or a midsole. All of these prior arrangements have incorporated, essentially, only a single closed fluid-containing system.
There is disclosed in this application a footwear structure which avoids the disadvantages of prior structures while affording additional structural and operating advantages.
An aspect is the provision of footwear structure which is characterized by improved cushioning and lateral stability, while affording shock absorption and forward thrust.
An important aspect is the provision of a footwear structure which includes two separate fluid-containing systems.
Another aspect is the provision of a footwear structure of the type set forth, wherein the fluid-containing systems are disposed within a structure including an outsole, a midsole and a flexible bladder.
Another aspect is the provision of a footwear structure of the type set forth, wherein at least one of the outsole and the midsole includes cavities for accommodating bladder pockets.
A still further aspect is the provision of a footwear structure of the type set forth, in which each of the fluid-containing systems includes cavities or pockets which are disposed outside the cavities or pockets of the other system.
Another aspect is the provision of a method of forming a footwear structure of the type set forth.